1. Field of the Invention
The present invention relates to broadcasting multimedia contents to mobile terminals and more particularly mobile telephones in a radiocommunication network.
2. Description of the Prior Art
In most prior art cellular radiocommunication networks a channel specific to each cell, called the cell broadcast channel (CBCH) in the GSM, is used to broadcast generally short information messages to mobile stations in the cell concerned. For clarity, that channel (and equivalent channels in other systems) will be referred to herein as a broadcast channel.
The information is made available to the user of a mobile terminal (for example a mobile telephone) in the form of a text message displayed on the screen of the mobile terminal, sounds, video sequences, or in the form of a voice message if the broadcast channel is a voice channel.
To receive this information, a mobile terminal must monitor the information channel, i.e. be constantly actively receiving that channel. Now it can happen that at certain times no broadcast message is being broadcast over the broadcast channel, for example because there is no new information to be broadcast. Mobile terminals cannot tell that no information will be broadcast at any particular time, and therefore are permanently actively receiving the broadcast channel, sometimes to no useful purpose. The same applies if some of the broadcast information is of no interest to the user of a mobile terminal.
In the case of a mobile telephone, permanently monitoring a channel that may contain no information or no information of interest to its user leads to heavy power consumption. Reducing the power consumption of mobile telephones so that their battery lasts as long as possible between charges is a constant concern. Another problem in this context relates to the radiocommunication network, which nowadays must convey more and more information, which may overload the network. The cost of transmitting these volumes of information can also be prohibitive.
Thus one object of the invention is to provide a broadcasting method enabling mobile terminals to receive only information of interest to them and that does not overload the network to no useful purpose.